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Author Archives: Russ
Author Archives: Russ
With the growing presence and sophistication of online threats like viruses, ransomware, and phishing scams, it’s increasingly important to have the right protection and tools to help protect your devices, personal information, and files from being compromised. Microsoft already provides robust security for Office services, including link checking and attachment scanning for known viruses and phishing threats, encryption in transit and at rest, as well as powerful antivirus protection with Windows Defender. Today, we’re announcing new advanced protection capabilities coming to Office 365 Home and Office 365 Personal subscribers to Continue reading
Reading a paper to build a research post from (yes, I’ll write about the paper in question in a later post!) jogged my memory about an old case that perfectly illustrated the concept of a positive feedback loop leading to a failure. We describe positive feedback loops in Computer Networking Problems and Solutions, and in Navigating Network Complexity, but clear cut examples are hard to find in the wild. Feedback loops almost always contribute to, rather than independently cause, failures.
Many years ago, in a network far away, I was called into a case because EIGRP was failing to converge. The immediate cause was neighbor flaps, in turn caused by Stuck-In-Active (SIA) events. To resolve the situation, someone in the past had set the SIA timers really high, as in around 30 minutes or so. This is a really bad idea. The SIA timer, in EIGRP, is essentially the amount of time you are willing to allow your network to go unconverged in some specific corner cases before the protocol “does something about it.” An SIA event always represents a situation where “someone didn’t answer my query, which means I cannot stay within the state machine, so I Continue reading